Counterbore facing tool



Nov. 7, 1967 D. G. BROOKS I COUNTERBORE FACING TOOL 2 Sheets-Sheet 1 Filed Dec. 23, 1966 DA RVI. 6. Bl? OOKS 4 INVENTOR r ATTORNEY Nov. 7, 1967 D. G. BROOKS 3,350,964

COUNTERBORE FACING TOOL Filed Dec. 23, 1966 2 Sheets$heet 2 W n' i I 'KII IHHH I 24 0A RYL G. BROOKS INVEN7UR y /Azwz ATTDIPNEV United States Patent Ofiice 3,350,964 Patented Nov. 7, 1967 3,350,964 COUNTERBORE FACING T901. Daryl G. Brooks, 3332 E. Sierra Madre Ave, Fresno, Calif. 93726 Filed Dec. 23, 1966, Ser. No. 604,310 9 Claims. (Cl. 82-4) This invention relates generally to cylinder boring tools and more particularly to hand tools for facing cylindrical surfaces.

In the maintenance and overhaul of diesel engines it is common practice to reestablish the upper counterbore seat to original tolerances when the cylinder sleeves are replaced. The diesel engines referred to are the type in which sleeves are inserted in and sealed to the block to form the cylinder, rather than the cylinder being bored in the block directly as in most automobile engines. The cylinder sleeves in such engines have an annular flange which projects radially outward at their upper end. The cylinder holes in the engine block in which the sleeves are inserted have a counterbore at their upper ends which forms a cylindrical rim upon which the annular flange rests to support the cylinder sleeve.

After engines of this type have undergone substantial service, wear occurs on the cylindrical rim of the counterbore in the block cylinder holes. More particularly, the upwardly directed surface or face of this counterbore is generally found to have worn more at certain points than at others so that a center axis normal to a plane passing through this surface of the counterbore does not align with the center axis of the block cylinder hole.

To correct these conditions so new cylinder sleeves inserted in the block cylinder holes will align properly with the pistons, the face of the counterbore must be trued-up. This operation of truing-up the upwardly directed surface or face of the counterbore is generally referred to as facmg.

Various tools have been previously developed to perform this function, however, most are quite expensive, and some are not sufficiently accurate to perform the job well.

It is therefore a major object of my invention to provide a tool for facing the upwardly directed surface of the counterbore in a diesel engine block cylinder hole, which is both accurate and inexpensive.

It is also the object of my inventin to provide a tool of the type described which is highly portable and capable of operation by a single person.

It is the further object of my invention to provide a tool of the type described whtch may be readily attached and detached from a cylinder block.

It is another object of my invention to provide a tool of the type described which can be conveniently used upon cylinder blocks which have not been removed from the vehicle chassis.

It is yet a further object of my invention to provide a tool of the type described which is hand operated and readily adjustable to the desired cut.

These and other objects and advantages of my invention will be more readily apparent from the following detailed description of a preferred embodiment of my invention and accompanying drawings in which:

FIGURE 1 is a perspective view of my tool assembled on the block of a diesel engine;

FIGURE 2 is an elevational view of my tool, in cross section;

FIGURE 3 is a bottom plan view of my tool; and

FIGURE 4 is an enlarged fragmentary elevational view of the cutting tool mounting in my tool.

. Referring now to the drawings and particularly FIG- URE 1 thereof, the numeral designates my facing tool generally. The tool consists of a housing 11, comprising a base plate 12 which is generally rectangular and has mounting holes 13 disposed at its corners, and a hub 14 which is bolted to one side of the base plate 12, with the axis of the hub substantially perpendicular to a plane through the base plate. The hub 14 is bushed for rotatably receiving a drive shaft 15.

The drive shaft 15 extends beyond the housing 11 at each end, has threads 16 at its lower end, and a radially directed hole 17 and adjustment threads 18 at its upper end. The adjustment threads 18, formed on the drive shaft 15 near its upper end, engage an adjustment collar which regulates the position of the shaft in the housing 11.

A tool carriage 19 is mounted on the lower end of the drive shaft 15 adjacent the threads 16 and abutted against shoulders Zll formed in the drive shaft, and is held in place by nut and washer 21.

The flats formed by the shoulders 20 prevent rotation between the drive shaft 15 and tool carriage 19.

The tool carriage 19 comprises a guide plate 22 which is in-cut to form cutter plate 23 and which has a cutter vise 24 mounted on its lower portion for carrying cutter 25. The guide plate 22 is accurately machined to a diameter slightly smaller than the diameter of the counterbore of the engine block upon which the tool is designed for use. When positioned in the counterbore, it thus serves to accurately align the longitudinal axis of the tool with the axis of the engine block cylinder hole. The cutter plate 23 is formed integrally and coaxially with guide plate 22 on its lower side and has a diameter substantially less than the diameter of the engine block cylinder hole itself. The cutter vise 24 is secured to the lower side of cutter plate 23 adjacent one point on its periphery. At this point, a radially directed slot 26 is provided in the cutter plate 23 which carries the cutter 25. The cutter vise 24 is held to the cutter plate 23 by screws 27 which can be loosened for adjustment or replacement of the cutter 25.

Scallops 28 are formed in the tool carriage 19 which correspond to scallops 29 formed in the base plate 12 when the drive shaft 15 is rotated to the proper position. These scallops provide means for visual observation of the counterbore face during the facing operation and allow easy escape for the cuttings.

To assure proper alignment between the drive shaft 15 and the the engine block cylinder hole, the lower surface of base plate 12 is machined to align with a plane disposed perpendicularly to the center axis of the drive shaft 15. A cylindrical recess 30 is formed in the lower surface of base plate 12, disposed concentrically about the center axis of the hub 14. The recess 30 is sufficiently large in diameter and of such depth that the tool carriage 19 may be drawn upwardly into the recess with nothing projecting below the lower surface of the base plate 12.

To regulate the position of drive shaft 15 in the hub 14, and thus position the tool carriage 19 with respect to the lower surface of base plate 12, an annular collar, stop collar 31, is provided. The collar has internal threads 33 which threadingly engage the adjustment threads 18 on the upper portion of drive shaft 15. The stop collar 31 is disposed above the hub 14, and the outer portion of the collar is knurled to provide a friction grip for manual turning. The collar also has a radially dis-posed set screw 34 for locking it at a fixed position on the drive shaft 15.

A bar handle 35 is provided which is snugly received in the hole 17 in the upper end of the drive shaft 15 to permit manual rotation of the drive shaft.

In operation the tool is used as follows:

After the head has been removed from the engine being repaired, and the cylinder sleeves extracted from the block cylinder holes, the facing tool 10 is set on the top surface of theb lock 40 in general alignment with one of the block cylinder holes 41. The base plate 12 of the tool is arranged to fit the block of a particular make of engine, for example, a Cummings Diesel C180. Particularly, the mounting holes 13 at the corners of the base plate 12 are aligned with the head studs 42 which extend out of the block 40 of this particular type engine. The tool is mounted to the engine block by passing the head studs 42 through the mounting holes 13 in the base plate 12. Since the head studs 42 extend a considerable distance above the base plate, spacer sleeves 43 are set over the head studs so that just a small portion at the upper end of the studs is exposed. Head nuts 44 are threaded on this exposed portion at the upper ends of the studs 42 and are turned tight to secure the base plate 11 firmly in place over the block cylinder hole 41.

Spacer sleeves 43 are not part of this invention, since they are commonly used to attach equipment to engine blocks.

Before tightening the head nuts 44 on the head studs 42, the tool is accurately positioned with respect to the counterbore 45 in the block cylinder hole 41 by threadedly backing off the annular stop collar 31 to permit the guide plate 22 of tool carriage 19 to extend below the lower surface of the base plate 11 and into the counterbore in the top of the block cylinder hole 41. The periphery of the guide plate 22, forming ac lose fit with the counterbore 45 of the cylinder hole 41, thereby accurately aligns the tool 10 with the cylinder hole.

With the tool 10 in this condition, the head nuts 44 are then tightened on the head studs 42 to secure the base plate 12 in proper position on the engine block 40. The tool 10 is then adjusted to a proper depth of cut by first raising the tool carriage 19 to its uppermost position in the housing 11 and then backing off the stop collar 31 until the cutter 25 just touches the face of the counterbore 45.

The collar is then backed off further a distance equal to the total depth of the cut desired, and the stop collar 31 fixed there by tightening set screw 34.

The operator then presses downwardly on the bar handle turning drive shaft until he can feel that the cutter is no longer engaging material. He then knows that his cutting pass has been completed.

The head nuts 44 securing the tool 10 to the block are then loosened and removed from the head studs 42 and the tool is freed from the block.

The tool is next applied to another cylinder hole 41 in the block and the same operation is repeated, and so on through all the block cylinder holes.

After each cylinder hole has been faced with the tool, as just described, shims of the thickness necessary to bring the counterbore back to original tolerance are placed on the counterbore face. Then new cylinder sleeves are placed in the block cylinder holes 41 with their annual flanges engaging the shimmed counterbores so that all dimensions involved are backed within factory tolerances.

As best shown in FIGURES 3 and 4, a hole 47 is provided in cutter plate 23 adjacent the inner end of cutter 25, to permit access for manual adjustment of the cutter, and a recess 48 is formed adjacent the outer end of the cutter for chips.

From this description of a preferred embodiment of my invention, it will be understood that I have provided an extremely simple tool for facing the surface of the block cylinder counterbore. The tool is easy to apply and remove, since it is quickly aligned with the cylinder hole by the guide plate, and easily secured in place by use of four head studs. The operation can be made even faster by use of a pneumatic wrench. Once the tool has been adjusted to the total depth of the cut desired on the particular engine, no further adjustment of this need be made, since the facing cut made in the counterbores of each cylinder hole will normally be the same. Therefore after adjusting the stop collar 31 for the depth desired on the first cylinder faced, no further adjustments are necessary for the remaining cylinder holes in the block.

It will also be understood, of course, that the tool is usable on engines of different types, with minor modifications. Since most shops are known to concentrate their repair work on two or three different engine types, this is a substantial advantage. The tool is adjusted to different engine types by merely unbolting and removing the base plate 12 from the housing 11 and the tool carriage 19 from the drive shaft 15. These are then replaced by a base plate and tool carriage which match the dimensions of the engine upon which the tool will be used.

In addition to being inexpensive to manufacture, my tool is manually operated, fast, and quite accurate. The accuracy is, of course, achieved by the guide plate having its periphery formed to snugly fit the counterbore in the cylinder hole, since it is the guide plate that accurately centers the tool with respect to the counterbore.

The tool may be readily disassembled, of course, for the substitution of base plates, tool carriages, or both when necessary to adapt it to different engine types.

From this detailed description it will be understood that my invention is capable of obtaining the objects and providing the advantages heretofore attributed to it. It should be further understood, that I do not mean to limit myself to particular details described, other than as set forth in the appended claims.

I claim: 1. A tool for facing the radial surface of a cylindrical counterbore, comprising:

tool carriage means having a longitudinal axis and including a cutting tool disposed for movement rotationally about and linearly in alignment with said longitudinal axis;

mounting means mounting said tool carriage means to the Work containing said cylindrical counterbore for simultaneous movement linearly along and rotationally about said longitudinal axis; and

alignment means operatively associated with said mounting means and said tool carriage means and disposed to align said longitudinal axis of said tool carriage means with the longitudinal axis of said cylindrical counterbore.

2. A tool as described in claim 1 which includes:

feed control means operatively associated with said tool carriage means and said mounting means, and disposed to control the linear movement of said tool carriage means along said longitudinal axis.

3. A tool as described in claim 1 in which:

said mounting means includes a housing having a longitudinal bore and a base plate removably attached to said housing and disposed for mounting engagement with the work containing said cylindrical counterbore with said housing bore substantially aligned with the center line of said cylindrical counterbore. 4. A tool as described in claim 1 in which: said tool carriage means includes a generally longitudinal drive shaft having a cutting tool mounted on one end thereof; and

said alignment means includes a generally cylindrical plate mounted on said drive shaft adjacent said cutting tool and having a diameter slightly less than the diameter of said cylindrical counterbore.

5. A tool as described in claim 1 in which:

said mounting means includes a housing having a longitudinal bore and a base plate removably attached to said housing and disposed for mounting engagement with the Work containing said cylindrical counterbore with said housing bore substantially aligned with the center line of said cylindrical counterbore;

said tool carriage means includes a generally longitudinal drive shaft having a cutting tool mounted on one end thereof;

said alignment means includes a generally cylindrical plate mounted on said drive shaft adjacent said cutting tool and having a diameter slightly less than the diameter of said cylindrical counterbore; and

which includes feed control means operatively associated with said tool carriage means and said mounting means, and disposed to control the linear movement of said tool carriage means along said longitudinal axis, said feed control means having an annular collar disposed on said drive shaft, adjacent the end thereof opposite the end having said cutting tool, and threadedly adjustable with respect thereto.

6. A tool for facing the radial surface of the counterbore in the cylinder hole of a diesel engine block, comprising:

a housing having a longitudinal bore therethrough;

a base plate interconnected with said housing, said base plate being disposed to mount said housing on said engine block with said housing bore in substantial alignment with the center line of said cylinder hole;

a drive shaft movably mounted in the bore of said housing and extending from each end thereof, and simultaneously movable rotatably and linearly with respect thereto;

drive means operatively associated with said drive shaft for eifecting said simultaneous movement thereof with respect to said housing;

a cylindrical guide plate mounted on the lower end of said drive shaft, and having a diameter slightly less than the diameter of said counterbore;

a cutting tool attached to said drive shaft adjacent said guide plate, and disposed to engage the radial surface of said counterbore when said drive shaft is moved as aforesaid; and

feed control means operatively associated with said drive shaft and housing, and disposed to limit the linear movement of said drive shaft into said cylinder hole.

7. A tool as described in claim 6 in which:

said base plate is removably secured to said housing,

and said base plate has a plurality of holes therethrough in substantial alignment with said housing bore and disposed to receive head studs of said engine block adjacent said cylinder hole; and

said guide plate is removably mounted on said drive shaft.

8. A tool as described in claim 6 in which:

said feed control means includes a collar mounted on the outer end of said drive shaft and threadedly adjustable with respect thereto, said. collar being disposed to engage said housing to limit downward movement of said drive shaft with respect to said housing and said cylinder hole.

9. A tool as described in claim 6 in which:

said cutting tool is adjustably mounted in a radially directed groove in said guide plate and extends radially outward from said groove a distance at least equal to the Width of said radial surface; and

said drive means includes manual gripping means on the upper end of said drive shaft.

References Cited UNITED STATES PATENTS HARRISON L. HINSON, Primary Examiner. 

1. A TOOL FOR FACING THE RADIAL SURFACE OF A CYLINDRICAL COUNTERBORE, COMPRISING: TOOL CARRIAGE MEANS HAVING A LONGITUDINAL AXIS AND INCLUIDING A CUTTING TOOL DISPOSED FOR MOVEMENT ROTATIONALLY ABOUT AND LINEARLY IN ALIGNMWNT WITH SAID LONGITUDINAL AXIS; MOUNTING MEANS MOUNTING SAID TOOL CARRIAGE MEANS TO THE WORK CONTAINING SAID CYLINDRICAL COUNTERBORE FOR SIMULTANEOUS MOVEMENT LINEARLY ALONG AND ROTATIONALL ABOUT SAID LONGITUDINAL AXIS; AND ALIGNMENT MEANS OPERATIVELY ASSOCIATED WITH SAID MOUNTING MEANS AND SAID TOOL MEANS AND DISPOSED TO ALIGN SAID LONGITUDINAL AXIS OF SAID TOOL CARRIAGE MEANS WITH THE LONGITUDINAL AXIS OF SAID CYLINDRICAL COUNTERBORE. 